The prior art is already aware of various mechanisms for clamping collets. Examples of the prior art are found in U.S. Pat. Nos. 809,296; 2,393,458; 2,466,651; 2,479,973; 2,562,455; 3,087,736; 3,632,122; 3,791,661; 4,614,469 and French Patent 2,379,351. These patents all show chucks or collet clamping arrangements, all for securing a workpiece to be worked upon. The function of these collets or chucks is to readily and securely clamp a workpiece so that the workpiece can be machined or the like.
The present invention differs over the prior art in that it provides a collet wherein the clamping force is precisely and uniformly applied to the collet so that the workpiece is accurately positioned and securely fixed. In actuality, the present mechanism applies full power of two actuating pistons which apply clamping force on diametrically opposite sides of a clamping sleeve. There is no binding or cocking of the moving and clamping parts, and the pistons are on the plane of clamping force. Further, there is four-sided guiding of the clamping mechanism which is arranged so that it can be accurately machined and ground to be square and accurate. Also, only two of the clamping parts need be heat treated to present the optimum mechanism in accuracy and strength.
Further, the activator utilized for the clamping action also restrains a sleeve, and thus the collet, from rotation to thereby, and again, accurately position the workpiece and affix it in that position.
Still further, the mechanism of this invention is arranged to be applied to two sets of collets and sleeves, and both sets can be activated simultaneously and thus two workpieces can be simultaneously clamped. Still further, the actuator is arranged so that it operates on the two sets in a manner wherein even two different diameters of workpieces can be simultaneously restrained in the two sets. That is, the one set can be displaced a greater amount than the other set to accommodate the clamping of the workpieces of the two different diameters and to do so simultaneously, all off one actuator and one application of clamping force. This is all achieved with a minimal of parts which are configured and related to each other so that they can be easily and accurately machined for the assembly and the features mentioned above.